1 <asp:FileUpload ID="fuPhoto1" onchange="javascript:__doPostBack('lbUploadPhoto','1')"  runat="server" ToolTip="选择图片" ForeColor="White" Width="68"/><br />
2 <img id="img" runat="server" src="" /><br />
3 <asp:FileUpload ID="fuPhoto2" onchange="javascript:__doPostBack('lbUploadPhoto','2')"  runat="server" ToolTip="选择图片" ForeColor="White" Width="68"/><br />
4 <asp:LinkButton ID="lbUploadPhoto" runat="server" OnClick="lbUploadPhoto_Click"></asp:LinkButton>

 1  /// <param name="e"></param>
 2         protected void lbUploadPhoto_Click(object sender, EventArgs e)
 3         {
 4             fileUpload(Request["__EVENTARGUMENT"]);
 5         }
 6         //从控件上传文件
 7         public void fileUpload(string number)
 8         {
 9             FileUpload fu = FindControl("fuPhoto"+number) as FileUpload;
10             if (fu.PostedFile != null && fu.PostedFile.ContentLength > 0)
11             {
12                 //1. 验证文件格式
13                 string ext = System.IO.Path.GetExtension(fu.PostedFile.FileName).ToLower();
14                 if (ext != ".jpg" && ext != ".gif" && ext != ".png")
15                 {
16                     Response.Write("文件非法！");
17                     return;
18                 }
19                 string savePath = Server.MapPath("~/upload/");//指定上传文件在服务器上的保存路径
20                 //2. 检查服务器上是否存在这个物理路径，如果不存在则创建
21                 if (!System.IO.Directory.Exists(savePath))
22                 {
23                     System.IO.Directory.CreateDirectory(savePath);
24                 }
25                 Random random = new Random(DateTime.Now.Millisecond);
26                 string fileName = DateTime.Now.ToString("yyMMddhhmmss") + random.Next(10000) + ext;
27                 string path = savePath + fileName;
28                 fu.PostedFile.SaveAs(path);
29                 Image img=FindControl("img"+number) as Image;
30                 img.Src = "upload/" + fileName;
31             }
32             else
33             {
34                 //没有图片的情况处理
35             }
36         }